Art of improving lubricating oils



. cohol esters.

Patented Nov. 18, 1941 2,263,265 ART OF IMPROVING LUBRIOATING oms Melvin F. Fincke, New York, N. Y., and Jefl'rey H. Bartlett, Cranford, N. J assignors to Standard Oil Development Company, a corporation of Delaware No Drawing.

Application February 24, 1938,

Serial No. 192,326

7 Claims.

The present invention relates to the art of improving lubricating oils, process oils. cutting oils. and Oils for working metals, particularly those having as a desirable characteristic a high penetrating or spreading quality. The invention will be fully understood from the following description.

In the manufacture of lubricating oils, process oils, metal working and cutting oils, as well as oils for other purposes, it is frequently desirable to enhance their natural penetrating ability and the closely related ability to spread over a large area. It has been found that unblended hydrocarbon and fatty oils differ considerably in this respect, even though they have substantially the same viscosity at the temperature of test. It

has been found also that the addition of certainmaterials to such oils, even in relatively small amounts, greatly increases their ability to spread over a wide area and to penetrate small crevices.

Among the materials that have been found to be most effective are the esters of carbonic acid. A relatively large number of esters of this type have been tested and it appears that this particular group of compounds possess to a marked extent the property of improving the penetrating and spreadingpower of oils.

In making up suitable compounds, various alcoholic esters of carbonic acid may be used such as methyl, ethyl, the propyl, butyl and amyl al- Even higher esters may be employed such as the esters of lauryl, cetyl and octadecyl alcohol. Cyclic aliphatic alcoholic esters may also be employed such as the carbonic esters of cyclohexanol. Phenyl or cresyl esters of carbonic acid may be employed, as well as other phenolic esters and aromatic alcoholic compounds such as benzyl carbonate. In some instances it is desirable to employ higher boiling esters so that they will not be lost by evaporation.

Not only are the pure esters of the types mentioned above useful, but mixed esters such as methyl-amyl carbonate, amyl-benzyl carbonate and butyl-phenyl carbonate may be employed.

The amount of the carbonate used is ordinarily quite small; for example, 1% often'produces a very pronounced effect, although generally the amount required is from 1 to 5%, more or less.

Carbonic esters may be added to motor lubricants as well as to oils for the lubrication of upper portions of the cylinders, and to lubricating oils for industrial purposes such as cutting oils and metal working oils.

It should be understood that the said carbonic esters are not intended to take the place of oriii) dinary ingredients employed in such products, but on the contrary the said esters are added to the oil base along with the other ingredients such as metal soaps, inhibitors of oxidation, corrosion and the like, extreme pressure compounds, or other specific materials added for some other particular purpose.

The following examples are presented as illustrations of the type of materials used and the results which may be obtained:

To a mineral lubricating oil having a viscosity of seconds Saybolt at 100 F., various amounts of different carbonic esters are added. The compounds are tested by blending with oil and placing drops of the blend of uniform size on a highly polished brass plate and allowing the same to stand at uniform temperature for a definite time, of the order of 20 to 24 hours. During this time the oil droplet gradually spreads and the area covered by the liquid is finally measured by a planimeter.

In the table below the data on some of these tests is assembled. In the first column, the composition is given; in the second column the time allowed for spreading, and in the third column the area to which the droplet spread is recorded in terms of the per cent covered by the unblended oil:

a M I v .e o egg Composition b0 3 0 5'3 3 5::

0'. Hours Percent Mineral oil (unblended) 100 Same+3.0% ethyl carbonate 125.8 20 Same+$% n-butyl carbonate 207.7 20 200 Same+'3.0% n-amyl carbonate 130 20 mm 22 Same+l.0% n-amyl carbonate do 24 125 Same+0.l% n-amyl carbonate do 24 100 The present invention is not to be limited to any theory of the action of the compounds which I are addedto the oils, nor to any particular ester compounds, but only to the following claims in which it is desired to claim all novelty inherent in the invention.

As used in the presentclaims, the expressions normal carbonic acid or normal carbonate signify a compound in which a carbon atom is attached directly to three oxygen atoms.

We claim:

1. An improved mineral lubricating oil of high spreading and penetrating ability comprising a mineral oil of the lubricating oil range having dissolved therein about 1% to about 5% of an ester or normal carbonic acid, the amount of said ester being suflicient to increase substantially the spreading and penetrating ability of said mineral oil.

2. Product according to claim 1 in which the ester is a cyclic alcoholic ester of normal carbonic acid.

3. Product according to claim 1 in which the ester is an aromatic ester of normal carbonic acid.

4. An improved mineral lubricating oil of high spreading and penetrating ability, suitable for use as a penetrating oil, comprising a mineral oil of the lubricating oil range havinz dissolved 15 therein about 1% to about 5% of an alkyl ester of normal carbonic acid, the amount of said ester being suflicient to increase substantially the spreading and penetrating ability of said mineral oil.

5. Product according to claim 4 in which the ester is a di-alkyl ester of normal carbonic acid.

6. Product according to claim 4 in which the ester is an alkyl ester of normal carbonic acid boiling above about 150 C.

7. Product according to claim 4 in which the ester is a normal butyl carbonate.

MELVIN F. FINCKE. JEFFREY H. BARTLETT. 

